emac_rx_size
mal_set_rcbs(dev->mal, dev->mal_rx_chan, emac_rx_size(new_mtu));
mal_set_rcbs(dev->mal, dev->mal_rx_chan, emac_rx_size(ndev->mtu));
int size = max(mtu + EMAC_MTU_OVERHEAD, emac_rx_size(mtu));
return SKB_DATA_ALIGN(emac_rx_size(mtu) + NET_IP_ALIGN);